The construction of semantic-based learning systems depends on the development of ontologies and the capacity to integrate and exploit knowledge using semantic technologies, notably RDF and ontologies. In this paper we present some concepts and ontologies defined in the context of the Active Semantic Learning System (Active SLS) that are used to describe resources and the semantic relation between these concepts defined in different ontologies. The purpose is to obtain a learning system that is capable of aggregating knowledge from different sources from the web and to exploiting that knowledge for the benefit of the learner.